This invention relates to presses of the kind (hereinafter referred to as the kind specified) comprising a body which includes a bed and a frame, a slide which is supported on the frame for reciprocation towards and away from the bed and means for so reciprocating the slide.
When a set of tools is fitted to a press, one part of the set being mounted on the bed and another part on the slide, it is necessary to ensure that the distance between the slide and the bed for accommodation of the tools corresponds to the height of the set of tools when closed. The distance between the slide and bed when the slide is in its bottom dead-center position is called herein the shut height of the press.
Presses which are intended to be fitted at different times with different sets of tools normally have a device for adjusting the shut height and such device is commonly adapted to adjust the position of the slide relative to a connecting rod by means of which drive is transmitted from a crankshaft of the press to the slide. Such adjustment device is also commonly associated with indicating means for indicating the position of the slide relative to the connecting rod, so that these can be set in a required relative position.
Different sets of tools which are fitted to a press sometimes require the press to have respective different strokes. Accordingly, means are provided in some presses of the kind specified for adjusting the stroke.
When a set of tools is fitted to a press, the shut height of the press is normally adjusted by a trial and error procedure. For example, the position of the slide relative to the connecting rod is adjusted to a position which the setter estimates to be the required relative position. The crankshaft of the press is then turned manually to move the slide towards the bed and, if the bottom dead-center position can be reached, the relative position of the tools is then ascertained and the position of the slide relative to the connecting rod adjusted accordingly. If the same set of tools is fitted to the press on a subsequent occasion, it is possible to reproduce the shut height previously found to be appropriate by setting the size of the stroke and the position of the slide relative to the connecting rod exactly as on the previous occasion. This procedure occupies a significant period of time. Furthermore, it may not be carried out accurately and before the press can be set into operation it is important that the trial and error procedure should be carried out with the crankshaft turned manually, in order to avoid the risk of damage to the tools and/or to the press.